


Impassable Despair

by FireFaceOutlook



Category: Undertale (Video Game)
Genre: Alternate Universe - Swapfell (Undertale), Gen, My own take, Swapfell Alphys (Undertale), Swapfell Chara (mentioned), Swapfell Papyrus (Undertale), Swapfell Sans (Undertale), Swapfell Undyne (mentioned), Younger Brother Papyrus (Undertale), swapfell red
Language: English
Status: In-Progress
Published: 2019-06-22
Updated: 2019-06-22
Packaged: 2020-05-16 10:18:38
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings, Major Character Death, No Archive Warnings Apply
Chapters: 1
Words: 971
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19316170
Author URL: https://archiveofourown.org/users/FireFaceOutlook/pseuds/FireFaceOutlook
Summary: He raised a hand, as if he was merely parting from Papyrus for their daily patrol, and grinned broadly despite the sudden cold drip of magic leaking from his eye sockets and over his sealed teeth.





	Impassable Despair

**Author's Note:**

> **A/N: Chara completed their genocide and chose to Erase the timeline when Frisk offered. However, they almost immediately reset after making their decision. That forced the monsters of Swapfell to suffer the consequences.**

“Keep up, Papyrus!”

“oh shove it, i'm going as fast as i can!”

Sans, a step ahead as he always was, saw the ground crumbling away in front of them first and tried to stop, but his boots slid on the perpetually soaked grass of Waterfall. Only Papyrus' reflexive use of blue magic – always on guard, having Sans' back, never letting his older brother's single hp lose even a decimal – prevented the shorter skeleton from disappearing into the yawning black below. On the other side of the expanding gap, Alphys stood, her glasses gleaming dimly in the artificial light, highlighting the cracks she never got fixed.

“Ca- Captain Sans! P-Papyrus!” she yelled, even as she was forced to retreat lest she fall victim to the unforeseen phenomena.

“Go, Alphys!” Sans ordered. “Get the civilians safely to Hotlands. We'll meet ya there!”

She hesitated, but being the loyal member of the Royal Guard that she was, she spun on her heels and sprinted away, obeying what could possibly be the last order she ever received from her superior and friend. Sans, safely back on his feet, followed Papyrus this time as they tried to find a spot to cross over to the last stretch to safety ** _[?]_**.

“Brother, are your shortcuts working yet?”

There was a slight falter in Papyrus' steps, then he was glancing back, right optic sparking with orange magic and [barely] concealed panic. “no. and i don't know **_why!_** ”

Sans didn't say anything, but looking at the endless black pit that was beginning to surround them, he found that he might have an idea as to 'why.' Papyrus stopped suddenly, and with his personalized boots – a gift from Undyne after they first moved from Hotland, to help prevent him from slipping on the slippery terrain –, he didn't end up on his tailbones like Sans often did if he wasn't careful. Sans managed to stop before collision with his brother's ridiculously long legs, and only then did he realize where they were. Somehow he hadn't noticed the ankle-deep water they'd been sprinting through, but there they stood, on the edge of the drop-off in Waterfall which was, ironically enough, a waterfall. On either side of them, the vanishing ground inched closer like a particularly vicious predator savoring its prey's last fearful moments.

“sans...?” Sans looked up at Papyrus, who was staring blankly over the edge of the waterfall and, oh, **_that was a familiar sight Sans had never wanted to see again._** His brother turned to him, and in a quivering voice, pleaded, “what do we do?”

Sans gazed up at his **_[baby]_** brother, and for the first time since the Core incident, didn't have an immediate answer. He'd failed Papyrus. **_Again._** His amnesia – swallowing the memories of their time in the Lab together, and the loss of their father to the cruel Royal Scientist. His fight with Chara – on their genocide run, **_just last timeline,_** his head being severed from his spinal column despite his best efforts to talk sense into the human. And now? They were going to die. Sometimes he wondered if it would've been better to have allowed Papyrus to choose his death in the past.

The glowing maroon pentagrams in his eye sockets spun at the thought, darting past Papyrus, towards the waterfall. Alphys had once mentioned, during their anime binge – or “human research,” as she called it –, that Undyne had gone on a tangent about Waterfall dropping off into a sort of wormhole that could be a passage to another reality entirely. And it's been a long time since Sans donned the mind of a scientist, but the fact of the manner was that the pit that the waterfall emptied into gave off the same **_[lack of]_** energy that the Void did. **_*hm..._**

“sans!”

Sans was suddenly pulled tightly against his brother, face buried in his damp tanktop – not his jacket, as it usually would've been, because they hadn't had time to grab it; Sans had woken Papyrus from a nap when the world began disappearing, and they'd left immediately – as the taller monster backed towards the edge of the falls. Managing to look back, Sans found that the area he'd stood upon was now gone, and the Void was lapping at his heels eagerly. Sans pushed himself to think. If the phenomena swallowed them, they would be lost, but if they leapt off of Waterfall... But surely there was only room for one of them to pass through without breaking it and shattering them across time and space like Dr. **[REDACTED]** did to their father and himself. And of course, Sans' duty as an older brother made putting his younger brother first a priority. So Sans looked up at Papyrus, who was glaring at the growing blankness with ferocity that scarcely masked his terror, and smiled, catching the other's attention.

“brother, what-”

Sans wrenched himself from Papyrus' loosening grip, easily brushing aside the hands that desperately reached for him in retaliation, and took a step back.

“Paps...”

The black had finally caught up, swallowing Sans' feet and dissolving his fibula into dust. Pressing his palms to his brother's chest, his left eye turned into a blazing gold star as he injected just enough magic into his bones to give a strong enough shove to send even well-balanced Papyrus stumbling back. The lanky skeleton's foot met nothing but air and the rest of his body followed suit. The dissolving process had already reached Sans ribs – the Void was really eating him up faster than he expected – so he had to make his final words count. He raised a hand, as if he was merely parting from Papyrus for their daily patrol, and grinned broadly despite the sudden cold drip of magic leaking from his eye sockets and over his sealed teeth.

“... see ya next **_fall._** ”

**Author's Note:**

> **A/N: I _know_ I have a lot of other works to be working on, _BUT_ I really like this idea, and I wanted to follow through with it. Also, I got the waterfall-wormhole idea from the Undertale Anniversary animation (look it up if you haven't seen it, it has the best Alphyne I've ever seen). Let me know if you like this so far and would like to see more!**


End file.
